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Rapid detection and characterization of sialic acid‐specific lectins of Helicobacter pylori
Author(s) -
LELWALAGURUGE JANAKI,
ASCENCIO FELIPE,
LJUNGH ÅSA,
WADSTRÖM TORKEL
Publication year - 1993
Publication title -
apmis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0903-4641
DOI - 10.1111/j.1699-0463.1993.tb00167.x
Subject(s) - sialic acid , antiserum , microbiology and biotechnology , fetuin , mucin , biology , lactoferrin , polyclonal antibodies , biochemistry , lectin , chemistry , glycoprotein , antigen , genetics
A particle agglutination assay (PAA) using fetuin (Ft) covalently coupled to carboxylate‐modified latex (CML) particles was evaluated for rapid detection of sialic acid‐specific haemagglutinins/lectins (SALs) of Helicobacter pylori isolates which bind sialoglycoconjugates. Sixty‐three percent (20/32) of the isolates examined gave a positive PAA test. Cell‐bound SALs were extracted by washing the bacteria with deionized water or isotonic saline, and their expression was influenced by pH and culture conditions. The Ft‐CML reactivity of the PAA‐positive isolates was inhibited by bovine submaxillary mucin, transferrin, fetuin, orosomucoid, vitronectin and lactoferrin in a manner which suggested that the isolates contain a lectin recognizing the α‐(2–6) linkage of terminal sialic acid. Western blots of strain NCTC 11637 SALs probed with horseradish peroxidase (HRP)‐labelled Ft identified three bands (MW 64 kD, 62 kD, 56 kD) which also reacted with HRP‐labelled mucin, transferrin, lactoferrin, orosomucoid, vitronectin and laminin. Sera from patients with a H. pylori infection and one polyclonal rabbit antiserum (strain NCTC 11637) also reacted with the SALs. Immunogold labelling of a polyclonal rabbit antiserum raised against the 64 kD protein of strain NCTC 11637 that reacted strongly with Ft‐CML showed that abundant SALs were loosely cell‐associated with the cell surface of both spiral and coccoidal forms of H. pylori. SALs were also present in low amounts on the surface of strain NCTC 11638 and 66, a clinical isolate that did not react with Ft‐CML.